This invention relates to prostaglandin derivatives and to a process for preparing them.
The prostaglandins and analogs are well-known organic compounds derived from prostanoic acid which has the following structure and atom numbering: ##STR4##
As drawn hereinafter the formulas represent a particular optically active isomer having the same absolute configuration as PGE.sub.1 obtained from mammalian tissues.
In the formulas, broken line attachments to the cyclopentane ring or side chain indicate substituents in alpha configuration, i.e. below the plane of the ring or side chain. Heavy solid line attachments indicate substituents in beta configuration, i.e. above the plane.
For background on prostaglandins, see for example Bergstrom et al., Pharmacol. Rev. 20, 1 (1968). For related compounds see Pace-Asciak et al., Biochem. 10, 3657 (1971). Related compounds are described in a publication on 6-keto-prostaglandin F.sub.1.alpha. by Pace-Asciak, J. Am. Chem. Soc. 98, 2348 (1976) and a publication on "PGX" (6,9.alpha.-oxido-9.alpha.,15.alpha.-dihydroxyprosta-(Z)5, (E)13-dienoic acid) by E. J. Corey et al., J. Am. Chem. Soc. 99, 20006 (1977).
Some of the compounds of this invention may be regarded as analogs of prostacyclin and prostacyclin-type compounds.
Prostacyclin, an organic compound related to prostaglandins, is (5Z)-9-deoxy-6,9.alpha.-epoxy-.DELTA..sup.5 -PGF.sub.1 and is represented by the formula ##STR5## For its synthesis and structure see for example R. A. Johnson et al., J. Am. Chem. Soc. 99, 4182 (1977) and Prostaglandins 12, 915 (1976), and E. J. Corey et al., cited above. For some of its biological properties and uses see the references cited in the Johnson references. Prostacyclin is referred to as "PGI.sub.2 ", see Anonymous, Prostaglandins 13, 375 (1977).